1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * fs/proc/vmcore.c Interface for accessing the crash
4 * dump from the system's previous life.
5 * Heavily borrowed from fs/proc/kcore.c
6 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
7 * Copyright (C) IBM Corporation, 2004. All rights reserved
8 *
9 */
10
11 #include <linux/mm.h>
12 #include <linux/kcore.h>
13 #include <linux/user.h>
14 #include <linux/elf.h>
15 #include <linux/elfcore.h>
16 #include <linux/export.h>
17 #include <linux/slab.h>
18 #include <linux/highmem.h>
19 #include <linux/printk.h>
20 #include <linux/memblock.h>
21 #include <linux/init.h>
22 #include <linux/crash_dump.h>
23 #include <linux/list.h>
24 #include <linux/moduleparam.h>
25 #include <linux/mutex.h>
26 #include <linux/vmalloc.h>
27 #include <linux/pagemap.h>
28 #include <linux/uaccess.h>
29 #include <linux/mem_encrypt.h>
30 #include <asm/io.h>
31 #include "internal.h"
32
33 /* List representing chunks of contiguous memory areas and their offsets in
34 * vmcore file.
35 */
36 static LIST_HEAD(vmcore_list);
37
38 /* Stores the pointer to the buffer containing kernel elf core headers. */
39 static char *elfcorebuf;
40 static size_t elfcorebuf_sz;
41 static size_t elfcorebuf_sz_orig;
42
43 static char *elfnotes_buf;
44 static size_t elfnotes_sz;
45 /* Size of all notes minus the device dump notes */
46 static size_t elfnotes_orig_sz;
47
48 /* Total size of vmcore file. */
49 static u64 vmcore_size;
50
51 static struct proc_dir_entry *proc_vmcore;
52
53 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
54 /* Device Dump list and mutex to synchronize access to list */
55 static LIST_HEAD(vmcoredd_list);
56 static DEFINE_MUTEX(vmcoredd_mutex);
57
58 static bool vmcoredd_disabled;
59 core_param(novmcoredd, vmcoredd_disabled, bool, 0);
60 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
61
62 /* Device Dump Size */
63 static size_t vmcoredd_orig_sz;
64
65 /*
66 * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
67 * The called function has to take care of module refcounting.
68 */
69 static int (*oldmem_pfn_is_ram)(unsigned long pfn);
70
register_oldmem_pfn_is_ram(int (* fn)(unsigned long pfn))71 int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn))
72 {
73 if (oldmem_pfn_is_ram)
74 return -EBUSY;
75 oldmem_pfn_is_ram = fn;
76 return 0;
77 }
78 EXPORT_SYMBOL_GPL(register_oldmem_pfn_is_ram);
79
unregister_oldmem_pfn_is_ram(void)80 void unregister_oldmem_pfn_is_ram(void)
81 {
82 oldmem_pfn_is_ram = NULL;
83 wmb();
84 }
85 EXPORT_SYMBOL_GPL(unregister_oldmem_pfn_is_ram);
86
pfn_is_ram(unsigned long pfn)87 static int pfn_is_ram(unsigned long pfn)
88 {
89 int (*fn)(unsigned long pfn);
90 /* pfn is ram unless fn() checks pagetype */
91 int ret = 1;
92
93 /*
94 * Ask hypervisor if the pfn is really ram.
95 * A ballooned page contains no data and reading from such a page
96 * will cause high load in the hypervisor.
97 */
98 fn = oldmem_pfn_is_ram;
99 if (fn)
100 ret = fn(pfn);
101
102 return ret;
103 }
104
105 /* Reads a page from the oldmem device from given offset. */
read_from_oldmem(char * buf,size_t count,u64 * ppos,int userbuf,bool encrypted)106 ssize_t read_from_oldmem(char *buf, size_t count,
107 u64 *ppos, int userbuf,
108 bool encrypted)
109 {
110 unsigned long pfn, offset;
111 size_t nr_bytes;
112 ssize_t read = 0, tmp;
113
114 if (!count)
115 return 0;
116
117 offset = (unsigned long)(*ppos % PAGE_SIZE);
118 pfn = (unsigned long)(*ppos / PAGE_SIZE);
119
120 do {
121 if (count > (PAGE_SIZE - offset))
122 nr_bytes = PAGE_SIZE - offset;
123 else
124 nr_bytes = count;
125
126 /* If pfn is not ram, return zeros for sparse dump files */
127 if (pfn_is_ram(pfn) == 0) {
128 tmp = 0;
129 if (!userbuf)
130 memset(buf, 0, nr_bytes);
131 else if (clear_user(buf, nr_bytes))
132 tmp = -EFAULT;
133 } else {
134 if (encrypted)
135 tmp = copy_oldmem_page_encrypted(pfn, buf,
136 nr_bytes,
137 offset,
138 userbuf);
139 else
140 tmp = copy_oldmem_page(pfn, buf, nr_bytes,
141 offset, userbuf);
142 }
143 if (tmp < 0)
144 return tmp;
145
146 *ppos += nr_bytes;
147 count -= nr_bytes;
148 buf += nr_bytes;
149 read += nr_bytes;
150 ++pfn;
151 offset = 0;
152 } while (count);
153
154 return read;
155 }
156
157 /*
158 * Architectures may override this function to allocate ELF header in 2nd kernel
159 */
elfcorehdr_alloc(unsigned long long * addr,unsigned long long * size)160 int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
161 {
162 return 0;
163 }
164
165 /*
166 * Architectures may override this function to free header
167 */
elfcorehdr_free(unsigned long long addr)168 void __weak elfcorehdr_free(unsigned long long addr)
169 {}
170
171 /*
172 * Architectures may override this function to read from ELF header
173 */
elfcorehdr_read(char * buf,size_t count,u64 * ppos)174 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
175 {
176 return read_from_oldmem(buf, count, ppos, 0, false);
177 }
178
179 /*
180 * Architectures may override this function to read from notes sections
181 */
elfcorehdr_read_notes(char * buf,size_t count,u64 * ppos)182 ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
183 {
184 return read_from_oldmem(buf, count, ppos, 0, mem_encrypt_active());
185 }
186
187 /*
188 * Architectures may override this function to map oldmem
189 */
remap_oldmem_pfn_range(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)190 int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
191 unsigned long from, unsigned long pfn,
192 unsigned long size, pgprot_t prot)
193 {
194 prot = pgprot_encrypted(prot);
195 return remap_pfn_range(vma, from, pfn, size, prot);
196 }
197
198 /*
199 * Architectures which support memory encryption override this.
200 */
201 ssize_t __weak
copy_oldmem_page_encrypted(unsigned long pfn,char * buf,size_t csize,unsigned long offset,int userbuf)202 copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
203 unsigned long offset, int userbuf)
204 {
205 return copy_oldmem_page(pfn, buf, csize, offset, userbuf);
206 }
207
208 /*
209 * Copy to either kernel or user space
210 */
copy_to(void * target,void * src,size_t size,int userbuf)211 static int copy_to(void *target, void *src, size_t size, int userbuf)
212 {
213 if (userbuf) {
214 if (copy_to_user((char __user *) target, src, size))
215 return -EFAULT;
216 } else {
217 memcpy(target, src, size);
218 }
219 return 0;
220 }
221
222 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
vmcoredd_copy_dumps(void * dst,u64 start,size_t size,int userbuf)223 static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
224 {
225 struct vmcoredd_node *dump;
226 u64 offset = 0;
227 int ret = 0;
228 size_t tsz;
229 char *buf;
230
231 mutex_lock(&vmcoredd_mutex);
232 list_for_each_entry(dump, &vmcoredd_list, list) {
233 if (start < offset + dump->size) {
234 tsz = min(offset + (u64)dump->size - start, (u64)size);
235 buf = dump->buf + start - offset;
236 if (copy_to(dst, buf, tsz, userbuf)) {
237 ret = -EFAULT;
238 goto out_unlock;
239 }
240
241 size -= tsz;
242 start += tsz;
243 dst += tsz;
244
245 /* Leave now if buffer filled already */
246 if (!size)
247 goto out_unlock;
248 }
249 offset += dump->size;
250 }
251
252 out_unlock:
253 mutex_unlock(&vmcoredd_mutex);
254 return ret;
255 }
256
257 #ifdef CONFIG_MMU
vmcoredd_mmap_dumps(struct vm_area_struct * vma,unsigned long dst,u64 start,size_t size)258 static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
259 u64 start, size_t size)
260 {
261 struct vmcoredd_node *dump;
262 u64 offset = 0;
263 int ret = 0;
264 size_t tsz;
265 char *buf;
266
267 mutex_lock(&vmcoredd_mutex);
268 list_for_each_entry(dump, &vmcoredd_list, list) {
269 if (start < offset + dump->size) {
270 tsz = min(offset + (u64)dump->size - start, (u64)size);
271 buf = dump->buf + start - offset;
272 if (remap_vmalloc_range_partial(vma, dst, buf, 0,
273 tsz)) {
274 ret = -EFAULT;
275 goto out_unlock;
276 }
277
278 size -= tsz;
279 start += tsz;
280 dst += tsz;
281
282 /* Leave now if buffer filled already */
283 if (!size)
284 goto out_unlock;
285 }
286 offset += dump->size;
287 }
288
289 out_unlock:
290 mutex_unlock(&vmcoredd_mutex);
291 return ret;
292 }
293 #endif /* CONFIG_MMU */
294 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
295
296 /* Read from the ELF header and then the crash dump. On error, negative value is
297 * returned otherwise number of bytes read are returned.
298 */
__read_vmcore(char * buffer,size_t buflen,loff_t * fpos,int userbuf)299 static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
300 int userbuf)
301 {
302 ssize_t acc = 0, tmp;
303 size_t tsz;
304 u64 start;
305 struct vmcore *m = NULL;
306
307 if (buflen == 0 || *fpos >= vmcore_size)
308 return 0;
309
310 /* trim buflen to not go beyond EOF */
311 if (buflen > vmcore_size - *fpos)
312 buflen = vmcore_size - *fpos;
313
314 /* Read ELF core header */
315 if (*fpos < elfcorebuf_sz) {
316 tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
317 if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
318 return -EFAULT;
319 buflen -= tsz;
320 *fpos += tsz;
321 buffer += tsz;
322 acc += tsz;
323
324 /* leave now if filled buffer already */
325 if (buflen == 0)
326 return acc;
327 }
328
329 /* Read Elf note segment */
330 if (*fpos < elfcorebuf_sz + elfnotes_sz) {
331 void *kaddr;
332
333 /* We add device dumps before other elf notes because the
334 * other elf notes may not fill the elf notes buffer
335 * completely and we will end up with zero-filled data
336 * between the elf notes and the device dumps. Tools will
337 * then try to decode this zero-filled data as valid notes
338 * and we don't want that. Hence, adding device dumps before
339 * the other elf notes ensure that zero-filled data can be
340 * avoided.
341 */
342 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
343 /* Read device dumps */
344 if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
345 tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
346 (size_t)*fpos, buflen);
347 start = *fpos - elfcorebuf_sz;
348 if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
349 return -EFAULT;
350
351 buflen -= tsz;
352 *fpos += tsz;
353 buffer += tsz;
354 acc += tsz;
355
356 /* leave now if filled buffer already */
357 if (!buflen)
358 return acc;
359 }
360 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
361
362 /* Read remaining elf notes */
363 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
364 kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
365 if (copy_to(buffer, kaddr, tsz, userbuf))
366 return -EFAULT;
367
368 buflen -= tsz;
369 *fpos += tsz;
370 buffer += tsz;
371 acc += tsz;
372
373 /* leave now if filled buffer already */
374 if (buflen == 0)
375 return acc;
376 }
377
378 list_for_each_entry(m, &vmcore_list, list) {
379 if (*fpos < m->offset + m->size) {
380 tsz = (size_t)min_t(unsigned long long,
381 m->offset + m->size - *fpos,
382 buflen);
383 start = m->paddr + *fpos - m->offset;
384 tmp = read_from_oldmem(buffer, tsz, &start,
385 userbuf, mem_encrypt_active());
386 if (tmp < 0)
387 return tmp;
388 buflen -= tsz;
389 *fpos += tsz;
390 buffer += tsz;
391 acc += tsz;
392
393 /* leave now if filled buffer already */
394 if (buflen == 0)
395 return acc;
396 }
397 }
398
399 return acc;
400 }
401
read_vmcore(struct file * file,char __user * buffer,size_t buflen,loff_t * fpos)402 static ssize_t read_vmcore(struct file *file, char __user *buffer,
403 size_t buflen, loff_t *fpos)
404 {
405 return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
406 }
407
408 /*
409 * The vmcore fault handler uses the page cache and fills data using the
410 * standard __vmcore_read() function.
411 *
412 * On s390 the fault handler is used for memory regions that can't be mapped
413 * directly with remap_pfn_range().
414 */
mmap_vmcore_fault(struct vm_fault * vmf)415 static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
416 {
417 #ifdef CONFIG_S390
418 struct address_space *mapping = vmf->vma->vm_file->f_mapping;
419 pgoff_t index = vmf->pgoff;
420 struct page *page;
421 loff_t offset;
422 char *buf;
423 int rc;
424
425 page = find_or_create_page(mapping, index, GFP_KERNEL);
426 if (!page)
427 return VM_FAULT_OOM;
428 if (!PageUptodate(page)) {
429 offset = (loff_t) index << PAGE_SHIFT;
430 buf = __va((page_to_pfn(page) << PAGE_SHIFT));
431 rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
432 if (rc < 0) {
433 unlock_page(page);
434 put_page(page);
435 return vmf_error(rc);
436 }
437 SetPageUptodate(page);
438 }
439 unlock_page(page);
440 vmf->page = page;
441 return 0;
442 #else
443 return VM_FAULT_SIGBUS;
444 #endif
445 }
446
447 static const struct vm_operations_struct vmcore_mmap_ops = {
448 .fault = mmap_vmcore_fault,
449 };
450
451 /**
452 * vmcore_alloc_buf - allocate buffer in vmalloc memory
453 * @sizez: size of buffer
454 *
455 * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
456 * the buffer to user-space by means of remap_vmalloc_range().
457 *
458 * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
459 * disabled and there's no need to allow users to mmap the buffer.
460 */
vmcore_alloc_buf(size_t size)461 static inline char *vmcore_alloc_buf(size_t size)
462 {
463 #ifdef CONFIG_MMU
464 return vmalloc_user(size);
465 #else
466 return vzalloc(size);
467 #endif
468 }
469
470 /*
471 * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
472 * essential for mmap_vmcore() in order to map physically
473 * non-contiguous objects (ELF header, ELF note segment and memory
474 * regions in the 1st kernel pointed to by PT_LOAD entries) into
475 * virtually contiguous user-space in ELF layout.
476 */
477 #ifdef CONFIG_MMU
478 /*
479 * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
480 * reported as not being ram with the zero page.
481 *
482 * @vma: vm_area_struct describing requested mapping
483 * @from: start remapping from
484 * @pfn: page frame number to start remapping to
485 * @size: remapping size
486 * @prot: protection bits
487 *
488 * Returns zero on success, -EAGAIN on failure.
489 */
remap_oldmem_pfn_checked(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)490 static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
491 unsigned long from, unsigned long pfn,
492 unsigned long size, pgprot_t prot)
493 {
494 unsigned long map_size;
495 unsigned long pos_start, pos_end, pos;
496 unsigned long zeropage_pfn = my_zero_pfn(0);
497 size_t len = 0;
498
499 pos_start = pfn;
500 pos_end = pfn + (size >> PAGE_SHIFT);
501
502 for (pos = pos_start; pos < pos_end; ++pos) {
503 if (!pfn_is_ram(pos)) {
504 /*
505 * We hit a page which is not ram. Remap the continuous
506 * region between pos_start and pos-1 and replace
507 * the non-ram page at pos with the zero page.
508 */
509 if (pos > pos_start) {
510 /* Remap continuous region */
511 map_size = (pos - pos_start) << PAGE_SHIFT;
512 if (remap_oldmem_pfn_range(vma, from + len,
513 pos_start, map_size,
514 prot))
515 goto fail;
516 len += map_size;
517 }
518 /* Remap the zero page */
519 if (remap_oldmem_pfn_range(vma, from + len,
520 zeropage_pfn,
521 PAGE_SIZE, prot))
522 goto fail;
523 len += PAGE_SIZE;
524 pos_start = pos + 1;
525 }
526 }
527 if (pos > pos_start) {
528 /* Remap the rest */
529 map_size = (pos - pos_start) << PAGE_SHIFT;
530 if (remap_oldmem_pfn_range(vma, from + len, pos_start,
531 map_size, prot))
532 goto fail;
533 }
534 return 0;
535 fail:
536 do_munmap(vma->vm_mm, from, len, NULL);
537 return -EAGAIN;
538 }
539
vmcore_remap_oldmem_pfn(struct vm_area_struct * vma,unsigned long from,unsigned long pfn,unsigned long size,pgprot_t prot)540 static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
541 unsigned long from, unsigned long pfn,
542 unsigned long size, pgprot_t prot)
543 {
544 /*
545 * Check if oldmem_pfn_is_ram was registered to avoid
546 * looping over all pages without a reason.
547 */
548 if (oldmem_pfn_is_ram)
549 return remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
550 else
551 return remap_oldmem_pfn_range(vma, from, pfn, size, prot);
552 }
553
mmap_vmcore(struct file * file,struct vm_area_struct * vma)554 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
555 {
556 size_t size = vma->vm_end - vma->vm_start;
557 u64 start, end, len, tsz;
558 struct vmcore *m;
559
560 start = (u64)vma->vm_pgoff << PAGE_SHIFT;
561 end = start + size;
562
563 if (size > vmcore_size || end > vmcore_size)
564 return -EINVAL;
565
566 if (vma->vm_flags & (VM_WRITE | VM_EXEC))
567 return -EPERM;
568
569 vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
570 vma->vm_flags |= VM_MIXEDMAP;
571 vma->vm_ops = &vmcore_mmap_ops;
572
573 len = 0;
574
575 if (start < elfcorebuf_sz) {
576 u64 pfn;
577
578 tsz = min(elfcorebuf_sz - (size_t)start, size);
579 pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
580 if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
581 vma->vm_page_prot))
582 return -EAGAIN;
583 size -= tsz;
584 start += tsz;
585 len += tsz;
586
587 if (size == 0)
588 return 0;
589 }
590
591 if (start < elfcorebuf_sz + elfnotes_sz) {
592 void *kaddr;
593
594 /* We add device dumps before other elf notes because the
595 * other elf notes may not fill the elf notes buffer
596 * completely and we will end up with zero-filled data
597 * between the elf notes and the device dumps. Tools will
598 * then try to decode this zero-filled data as valid notes
599 * and we don't want that. Hence, adding device dumps before
600 * the other elf notes ensure that zero-filled data can be
601 * avoided. This also ensures that the device dumps and
602 * other elf notes can be properly mmaped at page aligned
603 * address.
604 */
605 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
606 /* Read device dumps */
607 if (start < elfcorebuf_sz + vmcoredd_orig_sz) {
608 u64 start_off;
609
610 tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
611 (size_t)start, size);
612 start_off = start - elfcorebuf_sz;
613 if (vmcoredd_mmap_dumps(vma, vma->vm_start + len,
614 start_off, tsz))
615 goto fail;
616
617 size -= tsz;
618 start += tsz;
619 len += tsz;
620
621 /* leave now if filled buffer already */
622 if (!size)
623 return 0;
624 }
625 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
626
627 /* Read remaining elf notes */
628 tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
629 kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz;
630 if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
631 kaddr, 0, tsz))
632 goto fail;
633
634 size -= tsz;
635 start += tsz;
636 len += tsz;
637
638 if (size == 0)
639 return 0;
640 }
641
642 list_for_each_entry(m, &vmcore_list, list) {
643 if (start < m->offset + m->size) {
644 u64 paddr = 0;
645
646 tsz = (size_t)min_t(unsigned long long,
647 m->offset + m->size - start, size);
648 paddr = m->paddr + start - m->offset;
649 if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
650 paddr >> PAGE_SHIFT, tsz,
651 vma->vm_page_prot))
652 goto fail;
653 size -= tsz;
654 start += tsz;
655 len += tsz;
656
657 if (size == 0)
658 return 0;
659 }
660 }
661
662 return 0;
663 fail:
664 do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
665 return -EAGAIN;
666 }
667 #else
mmap_vmcore(struct file * file,struct vm_area_struct * vma)668 static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
669 {
670 return -ENOSYS;
671 }
672 #endif
673
674 static const struct proc_ops vmcore_proc_ops = {
675 .proc_read = read_vmcore,
676 .proc_lseek = default_llseek,
677 .proc_mmap = mmap_vmcore,
678 };
679
get_new_element(void)680 static struct vmcore* __init get_new_element(void)
681 {
682 return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
683 }
684
get_vmcore_size(size_t elfsz,size_t elfnotesegsz,struct list_head * vc_list)685 static u64 get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
686 struct list_head *vc_list)
687 {
688 u64 size;
689 struct vmcore *m;
690
691 size = elfsz + elfnotesegsz;
692 list_for_each_entry(m, vc_list, list) {
693 size += m->size;
694 }
695 return size;
696 }
697
698 /**
699 * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
700 *
701 * @ehdr_ptr: ELF header
702 *
703 * This function updates p_memsz member of each PT_NOTE entry in the
704 * program header table pointed to by @ehdr_ptr to real size of ELF
705 * note segment.
706 */
update_note_header_size_elf64(const Elf64_Ehdr * ehdr_ptr)707 static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
708 {
709 int i, rc=0;
710 Elf64_Phdr *phdr_ptr;
711 Elf64_Nhdr *nhdr_ptr;
712
713 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
714 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
715 void *notes_section;
716 u64 offset, max_sz, sz, real_sz = 0;
717 if (phdr_ptr->p_type != PT_NOTE)
718 continue;
719 max_sz = phdr_ptr->p_memsz;
720 offset = phdr_ptr->p_offset;
721 notes_section = kmalloc(max_sz, GFP_KERNEL);
722 if (!notes_section)
723 return -ENOMEM;
724 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
725 if (rc < 0) {
726 kfree(notes_section);
727 return rc;
728 }
729 nhdr_ptr = notes_section;
730 while (nhdr_ptr->n_namesz != 0) {
731 sz = sizeof(Elf64_Nhdr) +
732 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
733 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
734 if ((real_sz + sz) > max_sz) {
735 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
736 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
737 break;
738 }
739 real_sz += sz;
740 nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
741 }
742 kfree(notes_section);
743 phdr_ptr->p_memsz = real_sz;
744 if (real_sz == 0) {
745 pr_warn("Warning: Zero PT_NOTE entries found\n");
746 }
747 }
748
749 return 0;
750 }
751
752 /**
753 * get_note_number_and_size_elf64 - get the number of PT_NOTE program
754 * headers and sum of real size of their ELF note segment headers and
755 * data.
756 *
757 * @ehdr_ptr: ELF header
758 * @nr_ptnote: buffer for the number of PT_NOTE program headers
759 * @sz_ptnote: buffer for size of unique PT_NOTE program header
760 *
761 * This function is used to merge multiple PT_NOTE program headers
762 * into a unique single one. The resulting unique entry will have
763 * @sz_ptnote in its phdr->p_mem.
764 *
765 * It is assumed that program headers with PT_NOTE type pointed to by
766 * @ehdr_ptr has already been updated by update_note_header_size_elf64
767 * and each of PT_NOTE program headers has actual ELF note segment
768 * size in its p_memsz member.
769 */
get_note_number_and_size_elf64(const Elf64_Ehdr * ehdr_ptr,int * nr_ptnote,u64 * sz_ptnote)770 static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
771 int *nr_ptnote, u64 *sz_ptnote)
772 {
773 int i;
774 Elf64_Phdr *phdr_ptr;
775
776 *nr_ptnote = *sz_ptnote = 0;
777
778 phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
779 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
780 if (phdr_ptr->p_type != PT_NOTE)
781 continue;
782 *nr_ptnote += 1;
783 *sz_ptnote += phdr_ptr->p_memsz;
784 }
785
786 return 0;
787 }
788
789 /**
790 * copy_notes_elf64 - copy ELF note segments in a given buffer
791 *
792 * @ehdr_ptr: ELF header
793 * @notes_buf: buffer into which ELF note segments are copied
794 *
795 * This function is used to copy ELF note segment in the 1st kernel
796 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
797 * size of the buffer @notes_buf is equal to or larger than sum of the
798 * real ELF note segment headers and data.
799 *
800 * It is assumed that program headers with PT_NOTE type pointed to by
801 * @ehdr_ptr has already been updated by update_note_header_size_elf64
802 * and each of PT_NOTE program headers has actual ELF note segment
803 * size in its p_memsz member.
804 */
copy_notes_elf64(const Elf64_Ehdr * ehdr_ptr,char * notes_buf)805 static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
806 {
807 int i, rc=0;
808 Elf64_Phdr *phdr_ptr;
809
810 phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
811
812 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
813 u64 offset;
814 if (phdr_ptr->p_type != PT_NOTE)
815 continue;
816 offset = phdr_ptr->p_offset;
817 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
818 &offset);
819 if (rc < 0)
820 return rc;
821 notes_buf += phdr_ptr->p_memsz;
822 }
823
824 return 0;
825 }
826
827 /* Merges all the PT_NOTE headers into one. */
merge_note_headers_elf64(char * elfptr,size_t * elfsz,char ** notes_buf,size_t * notes_sz)828 static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
829 char **notes_buf, size_t *notes_sz)
830 {
831 int i, nr_ptnote=0, rc=0;
832 char *tmp;
833 Elf64_Ehdr *ehdr_ptr;
834 Elf64_Phdr phdr;
835 u64 phdr_sz = 0, note_off;
836
837 ehdr_ptr = (Elf64_Ehdr *)elfptr;
838
839 rc = update_note_header_size_elf64(ehdr_ptr);
840 if (rc < 0)
841 return rc;
842
843 rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
844 if (rc < 0)
845 return rc;
846
847 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
848 *notes_buf = vmcore_alloc_buf(*notes_sz);
849 if (!*notes_buf)
850 return -ENOMEM;
851
852 rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
853 if (rc < 0)
854 return rc;
855
856 /* Prepare merged PT_NOTE program header. */
857 phdr.p_type = PT_NOTE;
858 phdr.p_flags = 0;
859 note_off = sizeof(Elf64_Ehdr) +
860 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
861 phdr.p_offset = roundup(note_off, PAGE_SIZE);
862 phdr.p_vaddr = phdr.p_paddr = 0;
863 phdr.p_filesz = phdr.p_memsz = phdr_sz;
864 phdr.p_align = 0;
865
866 /* Add merged PT_NOTE program header*/
867 tmp = elfptr + sizeof(Elf64_Ehdr);
868 memcpy(tmp, &phdr, sizeof(phdr));
869 tmp += sizeof(phdr);
870
871 /* Remove unwanted PT_NOTE program headers. */
872 i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
873 *elfsz = *elfsz - i;
874 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
875 memset(elfptr + *elfsz, 0, i);
876 *elfsz = roundup(*elfsz, PAGE_SIZE);
877
878 /* Modify e_phnum to reflect merged headers. */
879 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
880
881 /* Store the size of all notes. We need this to update the note
882 * header when the device dumps will be added.
883 */
884 elfnotes_orig_sz = phdr.p_memsz;
885
886 return 0;
887 }
888
889 /**
890 * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
891 *
892 * @ehdr_ptr: ELF header
893 *
894 * This function updates p_memsz member of each PT_NOTE entry in the
895 * program header table pointed to by @ehdr_ptr to real size of ELF
896 * note segment.
897 */
update_note_header_size_elf32(const Elf32_Ehdr * ehdr_ptr)898 static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
899 {
900 int i, rc=0;
901 Elf32_Phdr *phdr_ptr;
902 Elf32_Nhdr *nhdr_ptr;
903
904 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
905 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
906 void *notes_section;
907 u64 offset, max_sz, sz, real_sz = 0;
908 if (phdr_ptr->p_type != PT_NOTE)
909 continue;
910 max_sz = phdr_ptr->p_memsz;
911 offset = phdr_ptr->p_offset;
912 notes_section = kmalloc(max_sz, GFP_KERNEL);
913 if (!notes_section)
914 return -ENOMEM;
915 rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
916 if (rc < 0) {
917 kfree(notes_section);
918 return rc;
919 }
920 nhdr_ptr = notes_section;
921 while (nhdr_ptr->n_namesz != 0) {
922 sz = sizeof(Elf32_Nhdr) +
923 (((u64)nhdr_ptr->n_namesz + 3) & ~3) +
924 (((u64)nhdr_ptr->n_descsz + 3) & ~3);
925 if ((real_sz + sz) > max_sz) {
926 pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
927 nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
928 break;
929 }
930 real_sz += sz;
931 nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
932 }
933 kfree(notes_section);
934 phdr_ptr->p_memsz = real_sz;
935 if (real_sz == 0) {
936 pr_warn("Warning: Zero PT_NOTE entries found\n");
937 }
938 }
939
940 return 0;
941 }
942
943 /**
944 * get_note_number_and_size_elf32 - get the number of PT_NOTE program
945 * headers and sum of real size of their ELF note segment headers and
946 * data.
947 *
948 * @ehdr_ptr: ELF header
949 * @nr_ptnote: buffer for the number of PT_NOTE program headers
950 * @sz_ptnote: buffer for size of unique PT_NOTE program header
951 *
952 * This function is used to merge multiple PT_NOTE program headers
953 * into a unique single one. The resulting unique entry will have
954 * @sz_ptnote in its phdr->p_mem.
955 *
956 * It is assumed that program headers with PT_NOTE type pointed to by
957 * @ehdr_ptr has already been updated by update_note_header_size_elf32
958 * and each of PT_NOTE program headers has actual ELF note segment
959 * size in its p_memsz member.
960 */
get_note_number_and_size_elf32(const Elf32_Ehdr * ehdr_ptr,int * nr_ptnote,u64 * sz_ptnote)961 static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
962 int *nr_ptnote, u64 *sz_ptnote)
963 {
964 int i;
965 Elf32_Phdr *phdr_ptr;
966
967 *nr_ptnote = *sz_ptnote = 0;
968
969 phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
970 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
971 if (phdr_ptr->p_type != PT_NOTE)
972 continue;
973 *nr_ptnote += 1;
974 *sz_ptnote += phdr_ptr->p_memsz;
975 }
976
977 return 0;
978 }
979
980 /**
981 * copy_notes_elf32 - copy ELF note segments in a given buffer
982 *
983 * @ehdr_ptr: ELF header
984 * @notes_buf: buffer into which ELF note segments are copied
985 *
986 * This function is used to copy ELF note segment in the 1st kernel
987 * into the buffer @notes_buf in the 2nd kernel. It is assumed that
988 * size of the buffer @notes_buf is equal to or larger than sum of the
989 * real ELF note segment headers and data.
990 *
991 * It is assumed that program headers with PT_NOTE type pointed to by
992 * @ehdr_ptr has already been updated by update_note_header_size_elf32
993 * and each of PT_NOTE program headers has actual ELF note segment
994 * size in its p_memsz member.
995 */
copy_notes_elf32(const Elf32_Ehdr * ehdr_ptr,char * notes_buf)996 static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
997 {
998 int i, rc=0;
999 Elf32_Phdr *phdr_ptr;
1000
1001 phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
1002
1003 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1004 u64 offset;
1005 if (phdr_ptr->p_type != PT_NOTE)
1006 continue;
1007 offset = phdr_ptr->p_offset;
1008 rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
1009 &offset);
1010 if (rc < 0)
1011 return rc;
1012 notes_buf += phdr_ptr->p_memsz;
1013 }
1014
1015 return 0;
1016 }
1017
1018 /* Merges all the PT_NOTE headers into one. */
merge_note_headers_elf32(char * elfptr,size_t * elfsz,char ** notes_buf,size_t * notes_sz)1019 static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
1020 char **notes_buf, size_t *notes_sz)
1021 {
1022 int i, nr_ptnote=0, rc=0;
1023 char *tmp;
1024 Elf32_Ehdr *ehdr_ptr;
1025 Elf32_Phdr phdr;
1026 u64 phdr_sz = 0, note_off;
1027
1028 ehdr_ptr = (Elf32_Ehdr *)elfptr;
1029
1030 rc = update_note_header_size_elf32(ehdr_ptr);
1031 if (rc < 0)
1032 return rc;
1033
1034 rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
1035 if (rc < 0)
1036 return rc;
1037
1038 *notes_sz = roundup(phdr_sz, PAGE_SIZE);
1039 *notes_buf = vmcore_alloc_buf(*notes_sz);
1040 if (!*notes_buf)
1041 return -ENOMEM;
1042
1043 rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
1044 if (rc < 0)
1045 return rc;
1046
1047 /* Prepare merged PT_NOTE program header. */
1048 phdr.p_type = PT_NOTE;
1049 phdr.p_flags = 0;
1050 note_off = sizeof(Elf32_Ehdr) +
1051 (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
1052 phdr.p_offset = roundup(note_off, PAGE_SIZE);
1053 phdr.p_vaddr = phdr.p_paddr = 0;
1054 phdr.p_filesz = phdr.p_memsz = phdr_sz;
1055 phdr.p_align = 0;
1056
1057 /* Add merged PT_NOTE program header*/
1058 tmp = elfptr + sizeof(Elf32_Ehdr);
1059 memcpy(tmp, &phdr, sizeof(phdr));
1060 tmp += sizeof(phdr);
1061
1062 /* Remove unwanted PT_NOTE program headers. */
1063 i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
1064 *elfsz = *elfsz - i;
1065 memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
1066 memset(elfptr + *elfsz, 0, i);
1067 *elfsz = roundup(*elfsz, PAGE_SIZE);
1068
1069 /* Modify e_phnum to reflect merged headers. */
1070 ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
1071
1072 /* Store the size of all notes. We need this to update the note
1073 * header when the device dumps will be added.
1074 */
1075 elfnotes_orig_sz = phdr.p_memsz;
1076
1077 return 0;
1078 }
1079
1080 /* Add memory chunks represented by program headers to vmcore list. Also update
1081 * the new offset fields of exported program headers. */
process_ptload_program_headers_elf64(char * elfptr,size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1082 static int __init process_ptload_program_headers_elf64(char *elfptr,
1083 size_t elfsz,
1084 size_t elfnotes_sz,
1085 struct list_head *vc_list)
1086 {
1087 int i;
1088 Elf64_Ehdr *ehdr_ptr;
1089 Elf64_Phdr *phdr_ptr;
1090 loff_t vmcore_off;
1091 struct vmcore *new;
1092
1093 ehdr_ptr = (Elf64_Ehdr *)elfptr;
1094 phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
1095
1096 /* Skip Elf header, program headers and Elf note segment. */
1097 vmcore_off = elfsz + elfnotes_sz;
1098
1099 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1100 u64 paddr, start, end, size;
1101
1102 if (phdr_ptr->p_type != PT_LOAD)
1103 continue;
1104
1105 paddr = phdr_ptr->p_offset;
1106 start = rounddown(paddr, PAGE_SIZE);
1107 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1108 size = end - start;
1109
1110 /* Add this contiguous chunk of memory to vmcore list.*/
1111 new = get_new_element();
1112 if (!new)
1113 return -ENOMEM;
1114 new->paddr = start;
1115 new->size = size;
1116 list_add_tail(&new->list, vc_list);
1117
1118 /* Update the program header offset. */
1119 phdr_ptr->p_offset = vmcore_off + (paddr - start);
1120 vmcore_off = vmcore_off + size;
1121 }
1122 return 0;
1123 }
1124
process_ptload_program_headers_elf32(char * elfptr,size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1125 static int __init process_ptload_program_headers_elf32(char *elfptr,
1126 size_t elfsz,
1127 size_t elfnotes_sz,
1128 struct list_head *vc_list)
1129 {
1130 int i;
1131 Elf32_Ehdr *ehdr_ptr;
1132 Elf32_Phdr *phdr_ptr;
1133 loff_t vmcore_off;
1134 struct vmcore *new;
1135
1136 ehdr_ptr = (Elf32_Ehdr *)elfptr;
1137 phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
1138
1139 /* Skip Elf header, program headers and Elf note segment. */
1140 vmcore_off = elfsz + elfnotes_sz;
1141
1142 for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
1143 u64 paddr, start, end, size;
1144
1145 if (phdr_ptr->p_type != PT_LOAD)
1146 continue;
1147
1148 paddr = phdr_ptr->p_offset;
1149 start = rounddown(paddr, PAGE_SIZE);
1150 end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
1151 size = end - start;
1152
1153 /* Add this contiguous chunk of memory to vmcore list.*/
1154 new = get_new_element();
1155 if (!new)
1156 return -ENOMEM;
1157 new->paddr = start;
1158 new->size = size;
1159 list_add_tail(&new->list, vc_list);
1160
1161 /* Update the program header offset */
1162 phdr_ptr->p_offset = vmcore_off + (paddr - start);
1163 vmcore_off = vmcore_off + size;
1164 }
1165 return 0;
1166 }
1167
1168 /* Sets offset fields of vmcore elements. */
set_vmcore_list_offsets(size_t elfsz,size_t elfnotes_sz,struct list_head * vc_list)1169 static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
1170 struct list_head *vc_list)
1171 {
1172 loff_t vmcore_off;
1173 struct vmcore *m;
1174
1175 /* Skip Elf header, program headers and Elf note segment. */
1176 vmcore_off = elfsz + elfnotes_sz;
1177
1178 list_for_each_entry(m, vc_list, list) {
1179 m->offset = vmcore_off;
1180 vmcore_off += m->size;
1181 }
1182 }
1183
free_elfcorebuf(void)1184 static void free_elfcorebuf(void)
1185 {
1186 free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
1187 elfcorebuf = NULL;
1188 vfree(elfnotes_buf);
1189 elfnotes_buf = NULL;
1190 }
1191
parse_crash_elf64_headers(void)1192 static int __init parse_crash_elf64_headers(void)
1193 {
1194 int rc=0;
1195 Elf64_Ehdr ehdr;
1196 u64 addr;
1197
1198 addr = elfcorehdr_addr;
1199
1200 /* Read Elf header */
1201 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
1202 if (rc < 0)
1203 return rc;
1204
1205 /* Do some basic Verification. */
1206 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1207 (ehdr.e_type != ET_CORE) ||
1208 !vmcore_elf64_check_arch(&ehdr) ||
1209 ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
1210 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1211 ehdr.e_version != EV_CURRENT ||
1212 ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
1213 ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
1214 ehdr.e_phnum == 0) {
1215 pr_warn("Warning: Core image elf header is not sane\n");
1216 return -EINVAL;
1217 }
1218
1219 /* Read in all elf headers. */
1220 elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
1221 ehdr.e_phnum * sizeof(Elf64_Phdr);
1222 elfcorebuf_sz = elfcorebuf_sz_orig;
1223 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1224 get_order(elfcorebuf_sz_orig));
1225 if (!elfcorebuf)
1226 return -ENOMEM;
1227 addr = elfcorehdr_addr;
1228 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1229 if (rc < 0)
1230 goto fail;
1231
1232 /* Merge all PT_NOTE headers into one. */
1233 rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
1234 &elfnotes_buf, &elfnotes_sz);
1235 if (rc)
1236 goto fail;
1237 rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
1238 elfnotes_sz, &vmcore_list);
1239 if (rc)
1240 goto fail;
1241 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1242 return 0;
1243 fail:
1244 free_elfcorebuf();
1245 return rc;
1246 }
1247
parse_crash_elf32_headers(void)1248 static int __init parse_crash_elf32_headers(void)
1249 {
1250 int rc=0;
1251 Elf32_Ehdr ehdr;
1252 u64 addr;
1253
1254 addr = elfcorehdr_addr;
1255
1256 /* Read Elf header */
1257 rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
1258 if (rc < 0)
1259 return rc;
1260
1261 /* Do some basic Verification. */
1262 if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
1263 (ehdr.e_type != ET_CORE) ||
1264 !vmcore_elf32_check_arch(&ehdr) ||
1265 ehdr.e_ident[EI_CLASS] != ELFCLASS32||
1266 ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
1267 ehdr.e_version != EV_CURRENT ||
1268 ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
1269 ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
1270 ehdr.e_phnum == 0) {
1271 pr_warn("Warning: Core image elf header is not sane\n");
1272 return -EINVAL;
1273 }
1274
1275 /* Read in all elf headers. */
1276 elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
1277 elfcorebuf_sz = elfcorebuf_sz_orig;
1278 elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1279 get_order(elfcorebuf_sz_orig));
1280 if (!elfcorebuf)
1281 return -ENOMEM;
1282 addr = elfcorehdr_addr;
1283 rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
1284 if (rc < 0)
1285 goto fail;
1286
1287 /* Merge all PT_NOTE headers into one. */
1288 rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
1289 &elfnotes_buf, &elfnotes_sz);
1290 if (rc)
1291 goto fail;
1292 rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
1293 elfnotes_sz, &vmcore_list);
1294 if (rc)
1295 goto fail;
1296 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1297 return 0;
1298 fail:
1299 free_elfcorebuf();
1300 return rc;
1301 }
1302
parse_crash_elf_headers(void)1303 static int __init parse_crash_elf_headers(void)
1304 {
1305 unsigned char e_ident[EI_NIDENT];
1306 u64 addr;
1307 int rc=0;
1308
1309 addr = elfcorehdr_addr;
1310 rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
1311 if (rc < 0)
1312 return rc;
1313 if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
1314 pr_warn("Warning: Core image elf header not found\n");
1315 return -EINVAL;
1316 }
1317
1318 if (e_ident[EI_CLASS] == ELFCLASS64) {
1319 rc = parse_crash_elf64_headers();
1320 if (rc)
1321 return rc;
1322 } else if (e_ident[EI_CLASS] == ELFCLASS32) {
1323 rc = parse_crash_elf32_headers();
1324 if (rc)
1325 return rc;
1326 } else {
1327 pr_warn("Warning: Core image elf header is not sane\n");
1328 return -EINVAL;
1329 }
1330
1331 /* Determine vmcore size. */
1332 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1333 &vmcore_list);
1334
1335 return 0;
1336 }
1337
1338 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1339 /**
1340 * vmcoredd_write_header - Write vmcore device dump header at the
1341 * beginning of the dump's buffer.
1342 * @buf: Output buffer where the note is written
1343 * @data: Dump info
1344 * @size: Size of the dump
1345 *
1346 * Fills beginning of the dump's buffer with vmcore device dump header.
1347 */
vmcoredd_write_header(void * buf,struct vmcoredd_data * data,u32 size)1348 static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data,
1349 u32 size)
1350 {
1351 struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf;
1352
1353 vdd_hdr->n_namesz = sizeof(vdd_hdr->name);
1354 vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name);
1355 vdd_hdr->n_type = NT_VMCOREDD;
1356
1357 strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME,
1358 sizeof(vdd_hdr->name));
1359 memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name));
1360 }
1361
1362 /**
1363 * vmcoredd_update_program_headers - Update all Elf program headers
1364 * @elfptr: Pointer to elf header
1365 * @elfnotesz: Size of elf notes aligned to page size
1366 * @vmcoreddsz: Size of device dumps to be added to elf note header
1367 *
1368 * Determine type of Elf header (Elf64 or Elf32) and update the elf note size.
1369 * Also update the offsets of all the program headers after the elf note header.
1370 */
vmcoredd_update_program_headers(char * elfptr,size_t elfnotesz,size_t vmcoreddsz)1371 static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz,
1372 size_t vmcoreddsz)
1373 {
1374 unsigned char *e_ident = (unsigned char *)elfptr;
1375 u64 start, end, size;
1376 loff_t vmcore_off;
1377 u32 i;
1378
1379 vmcore_off = elfcorebuf_sz + elfnotesz;
1380
1381 if (e_ident[EI_CLASS] == ELFCLASS64) {
1382 Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr;
1383 Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr));
1384
1385 /* Update all program headers */
1386 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1387 if (phdr->p_type == PT_NOTE) {
1388 /* Update note size */
1389 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1390 phdr->p_filesz = phdr->p_memsz;
1391 continue;
1392 }
1393
1394 start = rounddown(phdr->p_offset, PAGE_SIZE);
1395 end = roundup(phdr->p_offset + phdr->p_memsz,
1396 PAGE_SIZE);
1397 size = end - start;
1398 phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1399 vmcore_off += size;
1400 }
1401 } else {
1402 Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr;
1403 Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr));
1404
1405 /* Update all program headers */
1406 for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
1407 if (phdr->p_type == PT_NOTE) {
1408 /* Update note size */
1409 phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
1410 phdr->p_filesz = phdr->p_memsz;
1411 continue;
1412 }
1413
1414 start = rounddown(phdr->p_offset, PAGE_SIZE);
1415 end = roundup(phdr->p_offset + phdr->p_memsz,
1416 PAGE_SIZE);
1417 size = end - start;
1418 phdr->p_offset = vmcore_off + (phdr->p_offset - start);
1419 vmcore_off += size;
1420 }
1421 }
1422 }
1423
1424 /**
1425 * vmcoredd_update_size - Update the total size of the device dumps and update
1426 * Elf header
1427 * @dump_size: Size of the current device dump to be added to total size
1428 *
1429 * Update the total size of all the device dumps and update the Elf program
1430 * headers. Calculate the new offsets for the vmcore list and update the
1431 * total vmcore size.
1432 */
vmcoredd_update_size(size_t dump_size)1433 static void vmcoredd_update_size(size_t dump_size)
1434 {
1435 vmcoredd_orig_sz += dump_size;
1436 elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz;
1437 vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz,
1438 vmcoredd_orig_sz);
1439
1440 /* Update vmcore list offsets */
1441 set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
1442
1443 vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
1444 &vmcore_list);
1445 proc_vmcore->size = vmcore_size;
1446 }
1447
1448 /**
1449 * vmcore_add_device_dump - Add a buffer containing device dump to vmcore
1450 * @data: dump info.
1451 *
1452 * Allocate a buffer and invoke the calling driver's dump collect routine.
1453 * Write Elf note at the beginning of the buffer to indicate vmcore device
1454 * dump and add the dump to global list.
1455 */
vmcore_add_device_dump(struct vmcoredd_data * data)1456 int vmcore_add_device_dump(struct vmcoredd_data *data)
1457 {
1458 struct vmcoredd_node *dump;
1459 void *buf = NULL;
1460 size_t data_size;
1461 int ret;
1462
1463 if (vmcoredd_disabled) {
1464 pr_err_once("Device dump is disabled\n");
1465 return -EINVAL;
1466 }
1467
1468 if (!data || !strlen(data->dump_name) ||
1469 !data->vmcoredd_callback || !data->size)
1470 return -EINVAL;
1471
1472 dump = vzalloc(sizeof(*dump));
1473 if (!dump) {
1474 ret = -ENOMEM;
1475 goto out_err;
1476 }
1477
1478 /* Keep size of the buffer page aligned so that it can be mmaped */
1479 data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
1480 PAGE_SIZE);
1481
1482 /* Allocate buffer for driver's to write their dumps */
1483 buf = vmcore_alloc_buf(data_size);
1484 if (!buf) {
1485 ret = -ENOMEM;
1486 goto out_err;
1487 }
1488
1489 vmcoredd_write_header(buf, data, data_size -
1490 sizeof(struct vmcoredd_header));
1491
1492 /* Invoke the driver's dump collection routing */
1493 ret = data->vmcoredd_callback(data, buf +
1494 sizeof(struct vmcoredd_header));
1495 if (ret)
1496 goto out_err;
1497
1498 dump->buf = buf;
1499 dump->size = data_size;
1500
1501 /* Add the dump to driver sysfs list */
1502 mutex_lock(&vmcoredd_mutex);
1503 list_add_tail(&dump->list, &vmcoredd_list);
1504 mutex_unlock(&vmcoredd_mutex);
1505
1506 vmcoredd_update_size(data_size);
1507 return 0;
1508
1509 out_err:
1510 if (buf)
1511 vfree(buf);
1512
1513 if (dump)
1514 vfree(dump);
1515
1516 return ret;
1517 }
1518 EXPORT_SYMBOL(vmcore_add_device_dump);
1519 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1520
1521 /* Free all dumps in vmcore device dump list */
vmcore_free_device_dumps(void)1522 static void vmcore_free_device_dumps(void)
1523 {
1524 #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
1525 mutex_lock(&vmcoredd_mutex);
1526 while (!list_empty(&vmcoredd_list)) {
1527 struct vmcoredd_node *dump;
1528
1529 dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node,
1530 list);
1531 list_del(&dump->list);
1532 vfree(dump->buf);
1533 vfree(dump);
1534 }
1535 mutex_unlock(&vmcoredd_mutex);
1536 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
1537 }
1538
1539 /* Init function for vmcore module. */
vmcore_init(void)1540 static int __init vmcore_init(void)
1541 {
1542 int rc = 0;
1543
1544 /* Allow architectures to allocate ELF header in 2nd kernel */
1545 rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
1546 if (rc)
1547 return rc;
1548 /*
1549 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
1550 * then capture the dump.
1551 */
1552 if (!(is_vmcore_usable()))
1553 return rc;
1554 rc = parse_crash_elf_headers();
1555 if (rc) {
1556 pr_warn("Kdump: vmcore not initialized\n");
1557 return rc;
1558 }
1559 elfcorehdr_free(elfcorehdr_addr);
1560 elfcorehdr_addr = ELFCORE_ADDR_ERR;
1561
1562 proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
1563 if (proc_vmcore)
1564 proc_vmcore->size = vmcore_size;
1565 return 0;
1566 }
1567 fs_initcall(vmcore_init);
1568
1569 /* Cleanup function for vmcore module. */
vmcore_cleanup(void)1570 void vmcore_cleanup(void)
1571 {
1572 if (proc_vmcore) {
1573 proc_remove(proc_vmcore);
1574 proc_vmcore = NULL;
1575 }
1576
1577 /* clear the vmcore list. */
1578 while (!list_empty(&vmcore_list)) {
1579 struct vmcore *m;
1580
1581 m = list_first_entry(&vmcore_list, struct vmcore, list);
1582 list_del(&m->list);
1583 kfree(m);
1584 }
1585 free_elfcorebuf();
1586
1587 /* clear vmcore device dump list */
1588 vmcore_free_device_dumps();
1589 }
1590